why did you trust him? i don t know. i don t know. just a feeling. i didn t think he was gonna do anything wrong. the only reason why i agreed to do this is hopefully, it will cause parents to talk to their kids over and over again in ways that might save their lives. all right. i love you. she is a great kid. she is a great kid. reporter: our expert says there is one clear message you should give your kids. if you re going out and your kids are on their own, it s don t open the door for anybody unless the house is burning down and you re running out. reporter: don t answer the door no matter what seems like simple advice but as kids become mores inpen dent, it takes even more to keep them safe. so, for our next scenario, we are putting kids to the test where they least expect it. now, john the contractor will run into them on the street.
what do you think she will do? she will poe lightly decline. let s see if your kid would never do that. okay. reporter: as sophie steps out onto the sidewalk, john is right there to strike up a conversation. hey. what s up? did you decide on a paint for your room? he is good. reporter: our actor has sophie drawn in and keeps her talking. now, he is gonna try to get her in the vehicle. help me put this in? yeah. she is getting right by the truck. do you mind hopping in there so we can get it all the way in the back? i will hand it to you. you just want to jump on in there? hey, i will help you up. moment of truth. reporter: it looks like sophie s about to get in. hey, i will help you but then she refuses. her mom is overjoyed.
reporter: now, we have set up hidden cameras at a building a few blocks from eric s house. we will arrange it so eric runs into the friendly contractor again, this time, our actor will say he needs some help and ask eric to get in his truck. so, let me get your prediction. what do you think he will do? i think he will help and then when it s, like, hey, can you hop in the car, i think it s gonna click with eric, you know what i m not comfortable with that. eric, what s uup? john, remember me? reporter: will he walk away or fall for the trap? do you mind helping me out real quick? reporter: coming up, eric s home of decision. can you just go in the middle and i m going to happened this to you? reporter: and then two brothers are put to the test. dolly, what are you feeling right now? when dateline continues.
so, what are your predictions? i predict that sam will let him right in. how would you feel about it if he does let john right in? bad. i m already getting upset, like i didn t do the right thing. reporter: now, our hidden cameras are rolling and we are watching as john, the contractor, walks up to their house. [ door bell rings ] will sam remember what to do? or will he let him inside? my heart s pounding. coming up, sam s mom has told him the rules. i ve told him to hide. i have told him not to answer the door when i m not home. for no one. but when he sees the friendly contractor, will he remember what she said? oh, look. another anti-wrinkle cream in no hurry to make anything happen.
you know, he is really corey, an actor. oh, i did bad, didn t i? sam said he thought john could be trusted. he seemed like a nice guy but i sort of realize now that sometimes nice guys can be very bad ones. do you want to tell sam how you felt when he opened that door and what your reaction was? my heart was pounding and i started to cry. aw. it s all right. reporter: sam s mom says she is to blame for not teaching him that meeting someone once doesn t make them a safe person. this was a big teachable moment. yeah. reporter: so, for our next test, we found a mom who is convinced her 12-year-old daughter, danielle, will know what to do. i would say if i know them doesn t mean you know them. don t open the door if i m not home. don t talk to people who come by in the car. you feel like you have prepared her to pass the test? you know, i do. she says dan gel a born leader. she is an independent thinker.